House Mouse


Actual Size: 3 inches. With tail, 5″ to 8″ long

Characteristics: The house mouse is gray with a pointed nose and relatively large ears. Droppings are small, rod-shaped with pointed ends.

Habitat: Outside, they build nests near trees. Inside, they inhabit wall voids, cabinets, and garages.


  • House mice are most active overnight but can sometimes be seen during the day.
  • Inside, they will gravitate toward heat, moisture, and a wide variety of food.
  • They gain access through dime-sized holes, and beneath exterior doors.

House Mice in the North Bay and East Bay Area

House mice are one of the most common pest problems for homeowners in the Bay Area. They can squeeze through dime-sized cracks to gain entry into homes and buildings. House mouse fur varies in color from light brown to black, while the underbelly typically appears beige. Interestingly, the closer a house mouse lives in relation to humans, the darker the fur becomes. House mice nibble on small amounts of food, eating at dusk and before dawn. They are omnivores with a diet focused on seeds, roots, leaves, and stems. Female house mice can produce between 5 and 10 litters per year, with each litter containing anywhere from 5 to 12 young. Because they can reproduce so quickly, their infestations can become very large in little time.

House Mouse Environment

House mice can live in a variety of environments. They are found in and around both homes and businesses, making their homes in wall voids, storage boxes, attics, barns, sheds, basements, crawl spaces, cabinets, warehouses, and many other similar locations. During the fall and winter months, the colder temperatures drive these mice indoors, seeking shelter. House mice prefer to nest in dark, secluded areas and often build nests out of paper products, cotton, packing materials, wall insulation, and fabrics. House mice are nocturnal, but they can be spotted during the day when there is a more serious infestation.

House Mouse Habits & Threats

The house mouse will eat a variety of things, but they gravitate toward cereal and grains. House mice contaminate food and are implicated in the transmission of diseases such as salmonella and bubonic plague. The house mouse can cause significant damage to structures by gnawing and tunneling through walls. Mice have also been implicated in the generation of fires and explosions in homes and buildings. Chewed, exposed wires inside walls can spark, causing interior walls to catch fire.

If you have a house mouse infestation in your Bay Area property, contact your local rodent control experts!